摘要
植物-土壤生态系统土壤呼吸与温度、水分环境因子的关系对评价目前大气CO2浓度持续升高背景下陆地生态系统土壤碳库的变化趋势具有重要意义。依托FACE(freeaircarbondioxideenrichment)技术平台,利用阻断根法,采用LI-6400红外气体分析仪(IRGA)-田间原位测定的方法,研究了大气CO2体积分数升高对稻(OryzasativaL.)/麦(TriticumaestivumL.)轮作制中麦田的土壤呼吸、基础土壤呼吸和呼吸主要影响因子,分析了大气CO2体积分数升高后温度与水分对土壤呼吸的影响。结果表明,在整个测定期间,土壤呼吸与基础土壤呼吸速率呈明显的季节变化,与气温和土壤温度季节变化趋势基本一致,呼吸速率与温度具有显著的相关性,是影响土壤呼吸的控制性因素;呼吸速率与土壤含水量无显著的相关性,土壤水分是研究区麦田土壤CO2排放的非限制性因素,且温度与土壤含水量间的交互效应对土壤呼吸的影响不显著。基础土壤呼吸比作物下的土壤呼吸更易受温度影响,土壤温度比气温能更好地解释土壤CO2排放的季节性变化。而CO2体积分数增加降低了温度与呼吸速率间的相关系数和Q10,表明温度对土壤CO2排放的影响程度下降。但高CO2体积分数环境中植物-土壤生态系统的土壤呼吸对温度增加敏感性的降低,有利于减缓土壤碳分解损失的速度。结果有助于评价未来高CO2体积分数气候变暖背景下植物-土壤系统下的农田生态系统土壤碳的固定潜力。
The understanding of relationship of soil CO2 efflux and environmental factors （mainly for temperature, moisture） in the plant-soil ecosystem, within increasing atmospheric CO2 concentration context, will be important to evaluate the trend of soil carbon pool in terrestrial ecosystem. A Free-Air Carbon Dioxide Em-ichment （FACE） system and root-isolation methods were used to study the effects of elevated pCO2 on soil respiration, root-free soil respiration and theirs influencing factors, determined by in situ 1RGA （LI-6400） measurements, during the growth of wheat （Triticum aestivum L. cv Yangmai 14） for two consecutive seasons in a wheat /rice （Oryza sativa L.） rotation systeln. The effects of temperature and soil water content on soil CO2 effiux were analyzed under elevated pCO2. The results showed that the obvious seasonal variation about soil respiration and root-free soil respiration was observed, which was consistent with the variation of air and soil temperature. The significant exponential correlations were found both in the soil respiration to temperature and in the root-free soil respiration to temperature, whereas no significant correlabion between soil CO2 efflux and soil water content was observed. Which showed that temperature was the primary factor and soil moisture being the minor factor to the soil CO2 efflux in this experimental area. The interaction of temperature and moisture was non-significant. The root-free soil respiration was influenced more easily by temperature than soil respiration （including roots respiration）, and the seasonal variation of soil CO2 efflux could be explained much better by soil temperature than by air temperature. Moreover, elevated pCO2 dropped the exponential correlation coefficient of temperature and soil CO2 efflux and Q10, which suggested that the effect of temperature on soil CO2 efflux reduced under elevated pCO2. However, elevated pCO2 depressed the sensitivity of soil respiration to increment of soil temperature under plantsoil ecosystem, which might decrease the decomposition of soil carbon and promote the soil carbon sequestration. To sum up, these results will help in evaluating the soil organic carbon sequestration potential under the future higher [CO2] and climate wanning scenarios in arable ecosystem.
出处
《生态环境》
CSCD
北大核心
2008年第3期950-956,共7页
Ecology and Environmnet
基金
国家973项目(CCDMCTE-2002CB412502)
国家自然科学基金重点基金项目(40231003
40110817)
河南科技大学博士基金(09001266)
省基金(BK2006252)
关键词
CO2浓度升高
土壤呼吸
基础土壤呼吸
温度
土壤水分
农田
elevated pCO2
soil respiration
root-free soil respiration
temperature
soil moisture
cropland
